Uncertainty analysis for the ERBE active cavity radiometers

Abstract

The Earth Radiation Budget Experiment (ERBE) active cavity radiometers are used to measure the incoming solar, reflected-solar, and emitted longwave radiation from the Earth and its atmosphere. The radiometers are carried by the National Aeronautics and Space Administration's Earth Radiation Budget Satellite (ERBS) and the National Oceanic and Atmospheric Administration's NOAA-9 and NOAA-10 spacecraft. Four Earth-viewing nonscanning active cavity radiometers are carried by each platform. Two of the radiometers are sensitive to radiation in the spectral range from 0.2 to 50 micrometers , while the other two radiometers are sensitive to radiation in the spectral range from 0.2 to 5.0 micrometers . Each set of radiometers comes in a wide field-of-view (WFOV) and a medium field-of-view (MFOV) configuration. The cavities of the shortwave (visible) radiometers are covered with Suprasil dome to filter out the incoming longwave radiation. An absolute calibration of the radiometers was obtained by allowing them to view laboratory radiometric sources based upon the International Practical Temperature Scale of 1968 (IPTS68), and inflight stability of the radiometers is monitored by internal calibration sources.